31221152 has 12 divisors (see below), whose sum is σ = 61466706. Its totient is φ = 15610560.

The previous prime is 31221149. The next prime is 31221181. The reversal of 31221152 is 25112213.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 25441936 + 5779216 = 5044^2 + 2404^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 31221152.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 487799 + ... + 487862.

Almost surely, 2^31221152 is an apocalyptic number.

31221152 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

31221152 is a deficient number, since it is larger than the sum of its proper divisors (30245554).

31221152 is an equidigital number, since it uses as much as digits as its factorization.

31221152 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 975671 (or 975663 counting only the distinct ones).

The product of its digits is 120, while the sum is 17.

The square root of 31221152 is about 5587.5891044349. The cubic root of 31221152 is about 314.8833094275.

Adding to 31221152 its reverse (25112213), we get a palindrome (56333365).

The spelling of 31221152 in words is "thirty-one million, two hundred twenty-one thousand, one hundred fifty-two".